The overall objective of the proposed research is to identify and quantitatively analyze for all soluble phosphorus-containing metabolites in Dictyostelium discoideum. This organism is very widely used by developmental biologists to study the process of differentiation. In a 24 hr period under starvation conditions single-celled amoebae aggregate to form multicellular masses which eventually form two distinct cell types - stalk cells and spore cells. A spore, under correct conditions of temperature and humidity will release a single amoeba to start the cycle anew. With no exogenous nutrients entering the developing cells, D. discoideum is a closed system amenable to quantitative analysis of its metabolites. This we shall do for all soluble phosphorus-containing substances by examining perchloric acid extracts of cells at each stage of development using 31P nmr spectroscopy. Preliminary experiments disclose that about 40% of the soluble phosphorus-containing metabolites appear as a peak at 0.5 ppm in the 31P nmr spectrum. Purification by ion exchange chromatography, electrophoresis, and subsequent enzymatic degradation indicate this material is a group of small polynucleotides. These preliminary findings will be corroborated and the fate of this material will be determined at each stage of development using 31P nmr. Southern hybridization with D. discoideum DNA should show where this material comes from.